Tryphosella seasana, Lowry & Stoddart, 2009

Lowry, J. K. & Stoddart, H. E., 2009, Lysianassidae *, Zootaxa 2260 (1), pp. 561-597 : 593-595

Tryphosella seasana sp. nov.

( Figs 21 , 22 )

Type material. Holotype, female, ovigerous (3 eggs), 5.0 mm, AM P77905, east of Fitzroy Reef , Queensland, Australia (23°32'53"S 152°16'44"E), baited trap 3, 100 m, J.K. Lowry & K. Dempsey, MV Reefknot, 2-3 June 1994 ( QLD 1078 ) . Paratypes: male, 4.6 mm, AM P77906 ; male, 4.0 mm, AM P77907 ; female, 4.5 mm, AM P77908 ; 8 unsexed, AM P77909 ; 110 unsexed, AM P52156 ; same data as holotype . Paratypes: 32 unsexed, AM P52155 , east of Fitzroy Reef , Queensland, Australia (23°32'53"S 152°16'44"E), baited trap 1, 100 m, J.K. Lowry & K. Dempsey, MV Reefknot, 2-3 June 1994 ( QLD 1076 ) . Paratypes: 45 unsexed, AM P52157 , east of Fitzroy Reef , Queensland, Australia (23°32'53"S 152°16'44"E), baited trap 3, 100 m, J.K. Lowry & K. Dempsey, MV Reefknot, 3-4 June 1994 ( QLD 1096 ) .

Additional material examined. 3 unsexed, AM P52654 ( QLD 951 ); 23 unsexed, AM P52151 ( QLD 952 ); 45 unsexed, AM P52152 and AM P52656 ( QLD 953 ); 162 unsexed, AM P52153 and AM P52654 ( QLD 954 ); 454 unsexed, AM P52154 ( QLD 955 / SEAS); 1 male and 1 female, AM P48022 ( QLD 1198 ); 1 unsexed, AM P48029 ( QLD 1199 ) .

Type locality. East of Fitzroy Reef , Queensland, Australia (23°32'53"S 152°16'44"E), 100 m depth .

Etymology. Named for the SEAS (Scavengers of Eastern Australian Seas) project.

Description. Based on holotype female, 5.0 mm, AM P77905 and paratype female, 4.5 mm, AM P77908.

Head and body. Body without dorsal carina. Head lateral cephalic lobes rounded, with apically rounded margins. Antenna 1 slightly shorter than antenna 2; flagellum with strong 2-field callynophore, robust setae absent from proximal articles; calceoli absent; accessory flagellum with 4 articles. Antenna 2 less than 40% of body length; peduncular articles 3 to 5 not enlarged, without brush setae; calceoli absent. Mouthparts forming a subquadrate bundle. Epistome slightly produced beyond upper lip, broadly rounded. Mandible molar with asymmetrically reduced column, proximally setose, distally triturating; palp attached midway, article 3 with proximal A3-seta. Maxilla 1 outer plate with setal-teeth in 6/5 arrangement; setal-tooth 7, left and right symmetrical, cuspidate along most of sinsusoidal inner margin; palp distal margin with apical robust setae. Maxilliped inner plates well developed, about half the length of outer plate; outer plate with 2 long, slender apical robust setae; palp 4–articulate, article 4 well developed.

Pereon. Gnathopod 1 subchelate; coxa reduced, significantly shorter than coxa 2, tapering distally; basis sparsely setose along anterior margin; ischium long (length 3.1 x breadth); carpus long (length 3.1 x breadth), subequal in length to propodus, without posterior lobe; propodus longer than broad, margins subparallel, palm acute; dactylus inner face serrated. Gnathopod 2 subchelate; carpus 2.3 x length of propodus; palm transverse; dactylus minute. Pereopod 4 coxa with well developed posteroventral lobe. Pereopod 5 coxa equilobate; basis about as long as broad, posterior margin slightly serrated, with well developed wedge-shaped posteroventral lobe. Pereopod 7 basis posterior margin slightly serrated.

Pleon. Epimeron 3 posterior margin smooth, posterodistal corner acute. Urosomite 1 with anterodorsal notch and slightly rounded boss. Uropod 1 rami subequal. Uropod 2 rami subequal, inner ramus without marginal constriction. Uropod 3 with 1 plumose seta on inner ramus; rami subequal; outer ramus 2-articulate, article 2 long (about 0.5 x article 1); inner ramus extending beyond article 1 of outer ramus. Telson distinctly longer than broad, deeply cleft, with dorsal robust setae, with 1 apical robust seta on each lobe.

Male (sexually dimorphic characters). Based on paratype male, 4.6 mm, AM 77906. Antenna 1 flagellum with stronger 2-field callynophore; calceoli present. Antenna 2 about half body length; peduncular articles 4 and 5 with brush setae; calceoli present. Urosomite 1 anterodorsal notch slightly deeper. Uropod 3 with plumose setae on both rami.

Habitat. Scavenger on soft bottoms, 58 to 200 m depth.

Remarks. Tryphosella seasana and T. flynnana both live along the east coast of Australia in the same general habitat, but T. flynnana lives farther north and although they overlap in depth, T. flynnana is more common in shallower water. The main differences between these species are the shape of the gnathopod 1 coxa (short and tapering in T. flynnana , very short and almost subquadrate in T. seasana ) and the shape of gnathopod 2 palm (slightly obtuse in T. flynnana , transverse in T. seasana ). The very short, almost subquadrate coxa 1 separates T. seasana from all other GBR lysianassids.

Distribution. Australia. Queensland: east of Fitzroy Reef; east of Mooloolaba (current study).

Figures

FIGURE 21. Tryphosella seasana sp. nov., holotype female, 5.0 mm, AM P77905; habitus: paratype female, 4.5 mm, AM P77908; paratype male, 4.6 mm, AM P77906; east of Fitzroy Reef, Great Barrier Reef.

FIGURE 22. Tryphosella seasana sp. nov., holotype, female, 5.0 mm, AM P77905; paratype male, 4.6 mm, AM P77906; east of Fitzroy Reef, Great Barrier Reef.